无法使用replaceAll从字符串中删除单词

Question

if(containsAllWeather || containsAllWeather2){

            String weatherLocation = value.toString();

        if (weatherLocation != null){


                weatherLocation.replaceAll("how","")
                        .replaceAll("what","")
                        .replaceAll("weather", "")
                        .replaceAll("like", "")
                        .replaceAll(" in", "")
                        .replaceAll(" at", "")
                        .replaceAll("around", "");
        }

weatherLocation still gives exactly what the variable value includes and doesn't delete any of the words listed above.

This worked when I split weatherLocation to an array of strings, say, array of weatherLoc, and those lines of code worked for weatherLoc[1]

what am I doing wrong?

Answer 1

You need to assign the values returned by the method calls back to the String reference variable. Each time you do replaceAll() , it returns a new String object but your weatherLocation variable is still referencing to the original String.

  weatherLocation = weatherLocation.replaceAll("how","")
                    .replaceAll("what","")
                    .replaceAll("weather", "")
                    .replaceAll("like", "")
                    .replaceAll(" in", "")
                    .replaceAll(" at", "")
                    .replaceAll("around", "");

Answer 2

Strings are immutable. You need to assign the value of all those replaceAll calls to a variable and that will be what you want.

weatherLocation = weatherLocation.replaceAll("how","")
                .replaceAll("what","")
                .replaceAll("weather", "")
                .replaceAll("like", "")
                .replaceAll(" in", "")
                .replaceAll(" at", "")
                .replaceAll("around", "");

Answer 3

Try this:

weatherLocation = weatherLocation.replaceAll("how","")
                        .replaceAll("what","")
                        .replaceAll("weather", "")
                        .replaceAll("like", "")
                        .replaceAll(" in", "")
                        .replaceAll(" at", "")
                        .replaceAll("around", "");

Answer 4

String is immutable . So String.replaceAll returns a new instance of String . So you need to use like following

weatherLocation = weatherLocation.replaceAll("how","")
                .replaceAll("what","")
                .replaceAll("weather", "")
                .replaceAll("like", "")
                .replaceAll(" in", "")
                .replaceAll(" at", "")
                .replaceAll("around", "");